Method of reconstruction of diesel cylinder heads



June 17, 1969 R. H. JONES, JR., ET AL 3,

METHOD OF RECONSTRUCTION OF DIESEL CYLINDER HEADS Filed Oct. 11, 1966 United States Patent Casting, Iuc., RR. 1, Box 267, Hibbing, Minn. 55746 Filed Oct. 11, 1966, Ser. No. 585,928 Int. Cl. B23p 7/00; B22d 19/10 US. Cl. 29-401 4 Claims ABSTRACT OF THE DISCLOSURE A method of reconstructing Worn cylinder heads where only the inner face of the cylinder head forming a portion of a cylinder for a piston exhibits wear, including the steps of severing the worn portion from the remainder of the cylinder head, providing a new casting to be substituted for the worn portion, preparing the abutting surfaces of the unworn portion of the cylinder head and the new casting, applying a suitable epoxy adhesive to the surfaces and retaining the parts together and heat curing the adhesive. To provide accurate alignment, the central passage for an injector is counterbored into both the unworn head and the new casting at the abutting faces thereof, and an aligning sleeve is adhesively mounted in the counterbores.

The present invention relates to the reconstruction of castings and more particularly to a method of reconstructing worn castings such as worn diesel cylinder heads by replacing the worn-out portion of the casting.

Among the objects of the present invention is the provision of a novel method of reconstructing worn castings such as diesel cylinder heads by separating the wornout portion of the casting from the portion that does not exhibit wear and replacing the worn-out portion by bonding a new casting portion similar in structure to and equal to or of better quality than the worn-out portion to the remainder of the 01d casting.

Another object of the present invention is the provision of a method of reconstructing worn casting which is simpler and less expensive to produce than presently used methods. Previously, cracks in a casting were welded and valve seats were built up. However, it was found that where only certain portions of a casting were subject to normal wear and cracking, these portions could be replaced with the maintaining of the unworn portions of the casting. A new portion of the casting replaces the wornout portion with the new portion being bonded in a novel manner to the remaining portion of the original casting.

A further object of the present invention is the provision of a method of reconstructing a casting where the casting is sawed apart and the worn-out portion of the casting is scrapped or discarded and the unworn or usable portion of the casting is retained. A new casting portion to replace the worn-out portion is prepared and the adjoining surfaces of the casting portions are roughened and joined by a suitable heat curing adhesive compound and cured. Any additional machining required to finish the casting or smooth the joint is then performed and the casting is ready for use.

3,449,815 Patented June 17, 1969 The present invention also comprehends the provision of an aligning sleeve to be located in the injector passage by boring a small depth in the injector passage from the faces of the casting to be adhesively joined. The sleeve is inserted into one bored-out passage and the castings are adhesively joined; the sleeve aiding in alignment of the castings.

The present invention further comprehends a novel method of reconstructing a worn diesel cylinder head and thereby effecting a very substantial saving in the cost over replacement of the head.

Further objects are to provide a process of maximum simplicity, efficiency, economy and ease of operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby.

In the drawing:

FIGURE 1 is a side elevational view of a used cylinder head casting with the dotted line showing the plane of separation of the worn out portion of the casting.

FIG. 2 is a side elevational view of the unworn portion of the old casting with a new casting portion to be attached thereto to replace the worn part.

FIG. 3 is an end elevational view of the unworn portion of the old casting taken on the line 33 of FIG. 2.

FIG. 4 is an exploded partial View of the disassembled cylinder head, partly in cross section, showing the unworn portion of the old casting, the new casting portion and the aligning sleeve.

FIG. 5 is an enlarged partial side elevational view, part in cross section, showing the old casting, new casting and sleeve adhesively joined.

FIG. 6 is an enlarged partial side elevational view showing a steel ring bonded to the cylinder sealing surface.

Referring more particularly to the disclosure in the drawing wherein is shown an illustrative embodiment of a casting that is repaired by the new method of the present invention, FIG. 1 discloses a used casting 10 of a diesel cylinder head having a Worn-out lower portion 11 containing the valve seats and a relatively unworn upper portion 12. It has been found in diesel head castings and other types of similar castings that certain portions of a casting at or adjacent the valve seat face of a cylinder head exhibit wear while the remaining larger portion of the cylinder head does not show any substantial wear. Under previous maintenance practice, where the sealing surface is damaged, it was permissible to rework the head by cutting off up to 0.020 inch of the face. This was considered the absolute limit and if this limit was exceeded, the head would be scrapped due to lack of tolerance.

In the present invention, it has been found that approximately 2% inches of the lower end of the cylinder head can be removed, and a new casting 13 identical to the initial structure of this lower portion 11 can be bonded to the old casting. The upper portion 12 of the old casting does not exhibit any substantial wear and can be used with the addition of a new casting poriton 13 to replace the worn-out portion 11 of the old casting 10 without impairing the efficiency and operation of the cylinder head. The cylinder head provides at its inner face the valve seats for the valve stems (not shown) extending through passages 14 in the head to control the exhaust passages in the cylinder head and an injector (not shown) which is a high pressure fuel metering pump and spray valve combined in one housing which is complementarily received and seated in a tapered passage or hole 15 in the center of the cylinder head.

To aid in accurately aligning the unworn portion 12 of the old casting with the new casting portion 13, a seamless steel tubing sleeve 16 is utilized in the injector passage 15. The sleeves also provides added strength in the bonded area. Holes or counterbores 17 are fiycut or bored in the injection passage at the face 18 of the old casting portion and the face 19 of the new casting 13; the holes being cut approximately 0.010 to 0.020 inch larger and deeper than the sleeve so that adhesive can be applied between the sleeve and the castings.

The following steps are performed in preparing and bonding a new casting portion 13 providing the cylinder face 21 for the cylinder head. The old casting 10 is taken and the worn portion 11, corresponding to the new casting portion 13, is severed from the remaining portion 12 of the old or used casting 10 along the plane of line XX. The severed surface 18 of the retained portion 12 is ground or machined to provide proper dimensions of this casting. It is contemplated that a form of saw be used in the severing step which requires no further machining of the surface, and such grinding step would then be eliminated. Holes or counterbores 17 are bored in the injector passage in both the retained portion 12 and the new casting 13 for a seamless steel tubing sleeve 16 with the holes being approximately 0.010 to 0.020 inch larger and deeper than the sleeve. An example of such a sleeve has an outer diameter of approximately 1% inches, an inner diameter of approximately 1%. inches and a length of approximately 1 inch; although the dimensions of this example are not meant to be limiting. Next the surface of the retained casting 12 is sandblasted, gritblasted or other roughening surface treatment to provide a roughened surface for the adhesive. This roughened surface is then thoroughly cleaned.

The abutting bonding surface 19 of the new casting portion or cap 13 is then ground or machined followed by a sandblasting step to roughen this surface. This surface is then cleaned and ready for bonding. Suitable adhesive 22 is applied to the surface 18 of the retained head 12 as well as to the bored openings 17 in the head 12 and cap 13, and to the sleeve 16. The sleeve 16 is inserted into the bottom part of the head 12 and the cap 13 is placed on top of the head. Using a mallet or heavy hammer, the cap is rapped or pounded to assure thorough contact between the cap and head, and the assembly is heated to approximately 400 F. or more for an interval of approximately 30 minutes or more and then the casting is removed. The adhesive 22 cures during cooling to room temperature.

A suitable adhesive which will bond the old and new casting portions together and the sleeve 16 in the head 12 and cap 13, is a one part heat curing modified epoxy adhesive that is stable at room temperature. Such an adhesive is manufactured by the 3M Company and has a trade designation of EC 2214. Another 3M glue designated EC 2258 is also suitable for the purpose, although these examples are not meant to be limiting. The adhesive may be applied at temperatures of from approximately 50 F. to 150 F. and may be applied quickly in one of the following manners: (1) dipping and daubing with a sponge, spatula or other fiat object, (2) silk screening, or (3) with a pressure gun and a single spout nozzle which would be traced around the surface to be glued.

The curing time at elevated temperatures is shown in the following table:

TABLE I Time, approximate: Temperature, F. 1 hour 350 30 minutes 400 15 minutes 450 Curing longer than these stated times does not cause any undesirable consequences.

An additional step in the bonding process for castings involves the use of a mild steel ring 23 which is bonded to the flange 24 of the unworn upper casting portion 12 by the adhesive utilized to bond the casting portions together. This ring is of suitable dimensions to fit over the body portion of the casting 12 and has a thickness of approximately inch. Where the cylinder head retaining seating surface 25 on the flange 24 has been machined down to repair damaged sealing surfaces, the ring 23 will add metal to the surface after machining and will maintain original factory dimensions. The ring will be placed on the unworn cylinder portion 12 after the application of adhesive 22 to the surface 25 and at the same time as the sleeve 16 is located in the bore 17. The adhesive is then cured and the final casting machined, if necessary.

While a cylinder head casting of a particular shape has been shown and described by way of illustration, it is not my intent or desire to unnecessarily restrict the method of reconstruction by virtue of this limited showing.

We claim:

1. A method of reconstructing cylinder heads where only a portion of the head exhibits wear, comprising the steps of severing the worn cap of the cylinder head from the remainder of the head, providing a new casting of the severed cap to be substituted therefor, preparing the abutting surfaces of the retained cylinder head portions and the new casting of the cap, said cylinder head and new cap have a central passage for an injector, cutting a counterbore in the passage in each member at the abutting face, inserting a sleeve into the counterbores to accurately align the members, joining the adjoining surfaces of the cylinder head portion and the new portion of the cap together with a suitable adhesive, and heating and cooling the cylinder head portion and new cap to cure the adhesive, said counterbores being cut oversize to allow for adhesive to be placed in the counterbores prior to the positioning of the sleeve therein.

2. A method of reconstructing cylinder heads as set forth in claim 1, in which the casting and adhesive are heated to a temperature of at least 350 F. for at least one hour and then cooling the casting.

3. A method of reconstructing cylinder heads where only a portion of the head exhibits wear, comprising the steps of severing the worn cap of a cylinder head from the remainder of the head, providing a new casting identical to the original form of the severed cap to 'be substituted therefor, roughening the abutting surfaces of the retained cylinder head portion and the new casting of the cap, applying a suitable bonding agent to the adjoining surfaces, aligning and retaining the retained cylinder head portion and the new casting of the cap together, heating the retained cylinder head portion and the new casting of the cap to activate the bonding agent, cooling the bonded portions to provide a reconstructed cylinder head, and bonding a mild steel ring to the cylinder head retainer seating surface where such surface has been machined down due to damage thereto.

4. A method of reconstructing cylinder heads where only a portion of the head exhibits wear, comprising the steps of severing the worn cap of a cylinder head from the remainder of the head, providing a new casting identical to the original form of the severed cap to be substituted therefor, roughening the abutting surfaces of the retained cylinder head portion and the new casting of the cap, said cylinder head and new cap having a central passage for an injector, cutting counterbores in the central injector passage of the casting portions for an aligning sleeve, sandblasting the abutting surfaces, cleaning the sandblasted surfaces, applying a suitable adhesive to the abutting surfaces and the counterbores, inserting an aligining sleeve into the counterbore in the retained cylinder head portion, aligning and retaining the retained cylinder head portion and the new casting of the cap together, heating cylinder head.

Cheyette 241300 Caris 123195 X Hougen 29-401 X Fiechter 238-451 Morrison 12332 MARTIN P. SCHWADRON, Primary Examiner.

U.S. Cl. X.R.

5 the retained cylinder head portion and the new casting of 2,970,783 2/ 1961 the cap at a temperature of at least 350 F. for a time in- 2,996,050 8/1961 terval of at least one hour to activate the bonding agent, 3,051,279 8/ 1962 and cooling the bonded portion to provide a reconstructed 3,100,080 8/ 1963 5 3,187,729 6/1965 References Cited UNITED STATES PATENTS 1/1956 Brim I. C. COHEN, Assistant Examiner. 7/1956 Sheen 29401 10 9/1959 Piepho 29401 12/1960 Caris 123-193 92469 

